1. Field of the Invention
The present invention relates, in general, to a machine for welding rails of a track, including a machine frame mobile on the track, a rail pulling device comprising clamping members and hydraulic drives, and a welding unit. The invention further pertains to a method of welding rails of a track.
2. Description of the Related Art
Machines of this type for welding rails of a track have become known, for example, from U.S. Pat. No. 5,136,140, from European patent publication EP 0 326 794, or from U.S. Pat. No. 4,929,816. The welding operation is assisted by a rail pulling device which pulls the clamped rail ends towards one another with great force to a distance required for the welding process. The rail pulling device is suspended in pendulum-like fashion from a machine frame and is vertically adjustable for being lowered onto the rails in the course of working operations. In order to be able to properly grip the rails, these must first be lifted from the base plates they are resting on. This is done by driving wedges between the base plates and the rail base in a laborious manner.